1 /*
  2  * Copyright (c) 2017, 2021, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
  8  *
  9  * This code is distributed in the hope that it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * version 2 for more details (a copy is included in the LICENSE file that
 13  * accompanied this code).
 14  *
 15  * You should have received a copy of the GNU General Public License version
 16  * 2 along with this work; if not, write to the Free Software Foundation,
 17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18  *
 19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20  * or visit www.oracle.com if you need additional information or have any
 21  * questions.
 22  *
 23  */
 24 
 25 #include "precompiled.hpp"
 26 #include "gc/g1/g1CollectedHeap.hpp"
 27 #include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"
 28 #include "gc/g1/g1FullCollector.hpp"
 29 #include "gc/g1/g1FullCollector.inline.hpp"
 30 #include "gc/g1/g1FullGCCompactionPoint.hpp"
 31 #include "gc/g1/g1FullGCCompactTask.hpp"
 32 #include "gc/g1/heapRegion.inline.hpp"
 33 #include "gc/shared/gcTraceTime.inline.hpp"
 34 #include "logging/log.hpp"
 35 #include "oops/oop.inline.hpp"
 36 #include "utilities/ticks.hpp"
 37 
 38 // Do work for all skip-compacting regions.
 39 class G1ResetSkipCompactingClosure : public HeapRegionClosure {
 40   G1FullCollector* _collector;
 41 
 42 public:
 43   G1ResetSkipCompactingClosure(G1FullCollector* collector) : _collector(collector) { }
 44 
 45   bool do_heap_region(HeapRegion* r) {
 46     uint region_index = r->hrm_index();
 47     // Only for skip-compaction regions; early return otherwise.
 48     if (!_collector->is_skip_compacting(region_index)) {
 49 
 50       return false;
 51     }
 52     assert(_collector->live_words(region_index) > _collector->scope()->region_compaction_threshold() ||
 53          !r->is_starts_humongous() ||
 54          _collector->mark_bitmap()->is_marked(cast_to_oop(r->bottom())),
 55          "must be, otherwise reclaimed earlier");
 56     r->reset_skip_compacting_after_full_gc();
 57     return false;
 58   }
 59 };
 60 
 61 size_t G1FullGCCompactTask::G1CompactRegionClosure::apply(oop obj) {
 62   size_t size = obj->size();
 63   HeapWord* destination = cast_from_oop<HeapWord*>(obj->forwardee());
 64   if (destination == NULL) {
 65     // Object not moving
 66     return size;
 67   }
 68 
 69   // copy object and reinit its mark
 70   HeapWord* obj_addr = cast_from_oop<HeapWord*>(obj);
 71   assert(obj_addr != destination, "everything in this pass should be moving");
 72   Copy::aligned_conjoint_words(obj_addr, destination, size);
 73   cast_to_oop(destination)->init_mark();
 74   assert(cast_to_oop(destination)->klass() != NULL, "should have a class");
 75 
 76   return size;
 77 }
 78 
 79 void G1FullGCCompactTask::compact_region(HeapRegion* hr) {
 80   assert(!hr->is_pinned(), "Should be no pinned region in compaction queue");
 81   assert(!hr->is_humongous(), "Should be no humongous regions in compaction queue");
 82 
 83   if (!collector()->is_free(hr->hrm_index())) {
 84     G1CompactRegionClosure compact(collector()->mark_bitmap());
 85     hr->apply_to_marked_objects(collector()->mark_bitmap(), &compact);
 86     // Clear the liveness information for this region if necessary i.e. if we actually look at it
 87     // for bitmap verification. Otherwise it is sufficient that we move the TAMS to bottom().
 88     if (G1VerifyBitmaps) {
 89       collector()->mark_bitmap()->clear_region(hr);
 90     }
 91   }
 92 
 93   hr->reset_compacted_after_full_gc();
 94 }
 95 
 96 void G1FullGCCompactTask::work(uint worker_id) {
 97   Ticks start = Ticks::now();
 98   GrowableArray<HeapRegion*>* compaction_queue = collector()->compaction_point(worker_id)->regions();
 99   for (GrowableArrayIterator<HeapRegion*> it = compaction_queue->begin();
100        it != compaction_queue->end();
101        ++it) {
102     compact_region(*it);
103   }
104 
105   G1ResetSkipCompactingClosure hc(collector());
106   G1CollectedHeap::heap()->heap_region_par_iterate_from_worker_offset(&hc, &_claimer, worker_id);
107   log_task("Compaction task", worker_id, start);
108 }
109 
110 void G1FullGCCompactTask::serial_compaction() {
111   GCTraceTime(Debug, gc, phases) tm("Phase 4: Serial Compaction", collector()->scope()->timer());
112   GrowableArray<HeapRegion*>* compaction_queue = collector()->serial_compaction_point()->regions();
113   for (GrowableArrayIterator<HeapRegion*> it = compaction_queue->begin();
114        it != compaction_queue->end();
115        ++it) {
116     compact_region(*it);
117   }
118 }